Java===java Basic Learning (3)---Data type conversions, operator levels, enumeration types

Data type conversions:

Sometimes, a program needs to have a data type, such as int + float, and the result is a float, where int is converted to float type, which is a legal conversion.

The legitimate transformations in Java are as follows:

Red indicates no loss of information for the conversion, and Orange indicates a potential loss of progress.

 PackageTestbotoo; Public classShuzhileixingzhuanhuan { Public Static voidMain (string[] args) {intn = 123456789; floatf = n;//convert int type to float typeSystem.out.println (f);        //Forcing type conversions        Doublex = 9.9997; intNX = (int) x;//Strong turn operation, so that you can truncate the decimal part NX = 9//Of Course we can also perform rounding operations, using the Math.Round () method        DoubleX1 = 9.9997; intNX1 = (int) Math.Round (x1);                System.out.println (NX1); //Operation LevelA && B | | C equivalent to (a && b) | |c a+ = b + = c equivalent to A + = (b + =c) Operation level as shown in:}}

Conversion rules:

* If one of the two operands is a double type, the other operand is converted to a double type
* Otherwise, if one of the operands is of type float, the other operand will be converted to float type
* Otherwise, if one of the operands is of type long, the other operand will be converted to a long type
* Otherwise two operands will be converted to int type

Excerpt from: "Java Core technology" 3.5.5

Forced swap:

double x = 9.9997; int NX = (int// Strong turn operation, so it can truncate the decimal part NX = 9        // Of course we can also perform rounding operations, Used is the Math.Round () method Double x1 = 9.9997; int nx1 = (int) math.round (x1); System.out.println (NX1);

The level of the operator:

        A && B | | C equivalent to  (a && b) | | C         + = b + = c equivalent to   a + = (b + = c)

As shown in the following:

Java===java Basic Learning (3)---Data type conversions, operator levels, enumeration types